Machine performance standards

[john41es]

I am looking for information on interpreting the "circle/triangle/square" block used for evaluating the performance of milling machines. For example, loose gibs can cause affect the circularity of the block. I don't know if this is any sort of common standard; it has also been called a Euclid block.
Thanks

 

[Rleu]

Aerospace companys use this alot Circle diamond square. What I look for with this test is parrallel lines on the square with sharp corners (no over shoot) on the circle no withness marks on the quads ( X and Y axis changing direction) on the ones that I've seen the diamond has a ramp to check Z axis. If done correctly this test can be very helpfull in seeing the condition of your machine. I would suggest also running a Ball bar test, if you do this make sure that the ball bar person knows how to interpret the data.

Richard Leu
Cascade engineering and Service
Richard_Leu@hotmail.com

 

[john41es]

Do you check the parallelism of the x and y sides of the square with a micrometer? We do use a ballbar plot in our manufacturing of the machines, but our service technicians can't use them at the customers' shops, so we are training them to use these test cuts to help diagnose problems and therefore need a good understanding of what vibration, loose gibs, or head problems will look like when cutting.
Thanks for your help. Are you at Cascade Engineering in Bend, OR?

 

[Rleu]

The machine should cut X parallel and Y parallel but you have to check the actual square to check x to y, loose gibs will show up by possibly rounding the corners of the square. Looseness will show up on the circular interpolation as X&Y change direction you will notice witness marks but you have to be careful because this could be caused by excessive backlash in the screw a loose gib will often show as chatter all the way around the cut where a backlash problem should only show up at the quads. It would be better to ensure that all of the backlash has been looked at before this test. What type of machine is it? Cascade engineering and service is based out of Tacoma WA. I’m located north of Portland OR and I will soon be working for Selway Machine Tool Company in Oregon

Richard Leu
Selway Machine Tool
Richard_Leu@hotmail.com